The thermochemical equation for the combustion of hexane is shown below. C6H14(g) + 19/2Os(g) ==> 6CO2(g) + 7H2O(g) Delta H = -4163kJ What is the enthalpy change for the combustion of 2.50g C6H14?
2.50 g/86g = .029 mol
-4163kJ/.029 = -1.43 x 10^5kJ
Wrong. You have to MULTIPLY the heat of combustion (per mole) by the number of moles. You divided, instead.
Well, that's a lot of heat being released! It looks like the enthalpy change for the combustion of 2.50g of hexane is -1.43 x 10^5 kJ. That's enough to make you sweat, or maybe even turn you into a human torch! Just make sure to keep the fire extinguisher handy. Safety first!
To find the enthalpy change for the combustion of 2.50g of C6H14, we first need to calculate the number of moles of C6H14.
The molar mass of C6H14 is 86g/mol. So, the number of moles of C6H14 is given by:
2.50g / 86g/mol = 0.029 mol
Now, we can use the equation: ΔH = -4163 kJ to calculate the enthalpy change for the combustion of 2.50g of C6H14.
ΔH = -4163 kJ / 0.029 mol = -1.43 x 10^5 kJ/mol
Therefore, the enthalpy change for the combustion of 2.50g of C6H14 is approximately -1.43 x 10^5 kJ/mol.
To find the enthalpy change for the combustion of 2.50g of C6H14, we'll follow these steps:
1. Determine the number of moles of C6H14:
- The molar mass of C6H14 is 86g/mol.
- Divide the given mass (2.50g) by the molar mass to get the number of moles.
- In this case, 2.50g / 86g/mol = 0.029 mol.
2. Use the stoichiometry of the thermochemical equation to find the enthalpy change:
- The balanced equation shows that for each mole of C6H14 combusted, the enthalpy change is -4163 kJ.
- Divide the given enthalpy change (-4163 kJ) by the number of moles (0.029 mol) to find the enthalpy change per mole.
- In this case, -4163 kJ / 0.029 mol = -1.43 x 10^5 kJ.
Therefore, the enthalpy change for the combustion of 2.50g of C6H14 is -1.43 x 10^5 kJ.